One type of ink-jet printer includes a carriage that is reciprocated across a sheet of paper that is advanced through the printer. The reciprocating carriage holds an ink-jet pen very close to the paper. The pen is controlled by the printer for selectively ejecting ink drops from the pen while the pen moves across the paper, thereby to produce characters or an image on the paper.
The pen has a reservoir for holding a limited amount of ink. A relatively larger supply of ink is provided in a replaceable stationary container or cartridge that is mounted within the printer. A tube may be connected between the supply cartridge and the pen, thereby to conduct the flow of ink from the supply cartridge to the pen for replenishing the pen reservoir as needed.
An efficient and easy-to-use printer will include mechanisms that permit rapid replacement of a depleted collapsible cartridge without ink leakage from either the depleted cartridge or the full cartridge that is used as a replacement. Such a printer will also include a system for detecting the amount of ink in the stationary cartridge so that the printer may provide a signal that is indicative of the amount of ink remaining in a cartridge.